Surveillance of Australian workplace Based Respiratory Events (SABRE): notifications for the first 3.5 years and validation of occupational asthma cases

Our plain-English summary of Surveillance of Australian workplace Based Respiratory Events (SABRE): notifications for the first 3.5 years and validation of occupational asthma cases, by D. Elder, M. Abramson, D. Fish, et al (Occupational Medicine, 2004).

The study

• Authors: D. Elder, M. Abramson, D. Fish, A. Johnson, D. McKenzie, M. Sim
• Journal: Occupational Medicine
• Published: 2004;54(6):395-9
• Cited by: 21 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Aims: In Australia, the SABRE programme, a notification scheme, has been established to collect incidence data on occupational lung disease. This paper reports the first 3.5 years of this scheme and the results of an occupational asthma validation study.

Methods: A notification form is mailed regularly to thoracic physicians and occupational physicians in the Australian states of Victoria and Tasmania, who use this to report new cases of occupational lung disease. The validation study was performed by a blinded panel of two doctors, who reviewed information extracted from the medical files of a sample of reported cases of occupational asthma.

Results: A total of 520 diagnoses were reported. The mean (+/- SD) age of the 448 patients notified was 55.7 +/- 16.2 years. There were 394 (88%) males and 54 females. The most common single condition was asthma for which the most common causative agent was wood dust. However, the most commonly reported agent overall was asbestos. The validation study of occupational asthma found only fair agreement (kappa = 0.4) between the panel and notifying doctors. However, agreement was better (kappa = 0.5) when the analysis was restricted to those cases where the reporting doctor considered the likelihood of the diagnosis was high.

Conclusions: Occupational asthma is the most common occupational respiratory condition reported, which suggests increasing importance for this disease over more traditional forms of occupational lung disease. The validation study suggests that such schemes should restrict notifications only to those cases where the likelihood of the diagnosis is considered high.

In plain English

This paper described SABRE's first 3.5 years (November 1997 to April 2001): Victorian and Tasmanian respiratory and occupational physicians reported lung disease they judged work-related. 520 diagnoses were notified in 448 patients, 394 (88%) male. Asthma was commonest (170, 33%), most often attributed to wood dust. As a group, asbestos-related diseases were the commonest from a single causal agent (204 notifications). Reports included 120 of non-malignant pleural disease, predominantly plaque, and 42 of mesothelioma. Estimated occupational asthma incidence was 30.9 per million workers per year (95% CI 26.8 to 35.5). A blinded two-doctor panel reviewed de-identified file extracts for 40 notified occupational asthma cases and 43 patients the same five doctors saw for respiratory disease not thought work-related. Agreement with notifying doctors was only fair: kappa 0.34 (95% CI 0.18 to 0.49) and 0.32 (95% CI 0.18 to 0.50). It rose to moderate, 0.53 and 0.54 (each 95% CI 0.35 to 0.71), for cases the notifying doctor rated highly likely. The authors concluded such schemes should accept only highly likely diagnoses, noting small numbers and participation by only 49% of eligible doctors.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Report of a physician-based notification (surveillance) scheme for occupational lung disease, with a validation study in which a blinded panel of two doctors reviewed records of notified occupational asthma cases
• Who was studied: 520 diagnoses in 448 patients notified by respiratory and occupational physicians in Victoria and Tasmania, Australia, from November 1997 to April 2001. Mean age was 55.7 plus or minus 16.2 years (range 20 to 92).
• Exposure: Any workplace exposure, past or present, that the notifying doctor judged to have caused the disease. Asbestos was the most commonly reported single causal agent overall, and wood dust was the most common agent named for asthma.
• Main results:
  • Of the 448 patients, 394 (88%) were male and 54 (12%) female
  • Asthma was the most common notification, with 170 reports (33% of the 520 diagnoses)
  • Asbestos-related diseases, as a group, were the most commonly reported cases from a single causal agent, with 204 notifications
  • Non-malignant pleural disease, predominantly plaque, accounted for 120 diagnoses (23%), all but 2 reported by respiratory physicians
  • Mesothelioma accounted for 42 diagnoses (8%), all reported by respiratory physicians
  • Among asthma notifications, wood dust (including Western red cedar) was the most common agent, with 23 cases (13.5%)
  • Estimated incidence of occupational asthma was 30.9 (95% CI 26.8 to 35.5) cases per million workers per year
  • The male to female rate ratio for occupational asthma incidence was 2.4 (95% CI 1.8 to 3.4)
  • The validation sample was 40 notified occupational asthma cases and 43 other patients seen by the same five doctors for respiratory disease not thought to be work-related. Identifying data, and other data that could have revealed an obvious diagnosis, were removed from the copied files before the panel reviewed them.
  • Across all validation cases, agreement between the notifying doctor and the reviewers was only fair: observer A kappa 0.34 (95% CI 0.18 to 0.49), observer B kappa 0.32 (95% CI 0.18 to 0.50)
  • Restricted to cases the notifying doctor rated as highly likely, agreement rose to moderate: observer A kappa 0.53 (95% CI 0.35 to 0.71), observer B kappa 0.54 (95% CI 0.35 to 0.71)
  • Agreement between the two reviewers was moderate (kappa 0.48, 95% CI 0.31 to 0.63) and was 0.53 when restricted to high-likelihood cases
• The authors' conclusion: The authors concluded that occupational asthma was the most commonly reported occupational respiratory condition, which they said suggests its increasing importance over more traditional occupational lung diseases. They also concluded that such schemes should accept notifications only of diagnoses considered highly likely.
• Limitations the authors state:
  • The validation study numbers were small
  • Blinding the review panel may have removed relevant information, which could have reduced agreement
  • Because of privacy and ethics restrictions, reviewers had no access to the patients or to uncensored records
  • The most prolific reporters may have had a lower threshold for diagnosing occupational asthma
  • Cases were likely under-reported: the scheme was new and only 49% of eligible doctors took part
  • Findings may not apply to Australia as a whole, since some high-risk sectors such as underground mining operate mostly in non-participating states
  • The scheme had run only 42 months, so absolute numbers were small and a different pattern may emerge

Topics

Medical terms in this study, explained in our Lexicon: Occupational Lung Disease.

Related studies

• Surveillance of Australian workplace Based Respiratory Events (SABRE) in New South Wales — K. Hannaford-Turner, D. Elder, et al. (2010)
• Relation of occupational exposure to respiratory symptoms and asthma in a general population sample: self-reported versus interview-based exposure data — P.S. Bakke, R. Hanoa, et al. (2001)
• Vapor, dust, and smoke exposure in relation to adult-onset asthma and chronic respiratory symptoms: the Singapore Chinese Health Study — T.D. LeVan, W.P. Koh, et al. (2006)
• Irregular opacities in the lung, occupational asthma, and airways dysfunction in aluminum workers — K.H. Kilburn, R.H. Warshaw (1992)
• SWORD '93. Surveillance of work-related and occupational respiratory disease in the UK — B.A. Sallie, D.J. Ross, et al. (1994)
• SWORD '94: surveillance of work-related and occupational respiratory disease in the UK — D.J. Ross, B.A. Sallie, et al. (1995)

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